Colombo: An international human rights group alleges Sri Lankan security forces continue to use torture, rape and other forms of sexual violence against suspected members of the Tamil Tiger rebels and their supporters, nearly four years after the end of the country's civil war. The military denied the allegations.

In a report released Tuesday, New York-based Human Rights Watch said that although the decades-long war ended in May 2009, politically motivated sexual violence against suspects in custody continues to this day. It called for an international investigation into the practice.

"Sri Lankan security forces have committed untold numbers of rapes of Tamil men and women in custody," said Brad Adams, the group's Asia director.

"These are not just wartime atrocities but continue to the present, putting every Tamil man and woman arrested for suspected LTTE involvement at serious risk," Adams said, using the acronym for the Liberation Tigers of Tamil Eelam, the formal name of the rebels.

The violent 26-year war saw ethnic minority Tamil rebels fighting for their own homeland against troops from the Sinhalese majority government. More than 100,000 people were killed on both sides before the government crushed the rebels with a bloody push into rebel-controlled northern areas. A U.N. report has said tens of thousands of civilians were killed in the final five months of fighting alone.

The rebels themselves have been accused of widespread atrocities, including holding civilians as human shields, using child soldiers and killing people who tried to leave areas under their control.

The report comes as the United Nations Human Rights Council is set to discuss Sri Lanka's alleged wartime abuses at its annual meeting in Geneva this week. The United States has said it will introduce a resolution at the meeting urging a full accounting of what happened at the end of the war.

The 41-page report, titled "'We Will Teach You a Lesson': Sexual Violence against Tamils by Sri Lankan Security Forces," provides detailed accounts of 75 cases of alleged rape and sexual abuse that occurred from 2006-2012 in both official and secret detention centers throughout Sri Lanka.

Human Rights Watch said most of the victims spoke to them outside of Sri Lanka, and it corroborated their accounts with medical and legal reports. Because Human Rights Watch was not able to openly conduct research in Sri Lanka or interview people still in custody, it said the cases in its report likely represent only a tiny fraction of custodial rape in political cases.

It said many of the cases followed a pattern of an individual being abducted from home by unidentified men, taken to a detention center, and abusively interrogated about alleged activities of the rebels. It said men and women reported being raped on multiple days, often by several people, with the army, police, and pro-government paramilitary groups frequently participating.

The victims also described being beaten, hung by their arms, partially asphyxiated, and burned with cigarettes. None of those who spoke to Human Rights Watch had access to legal counsel, family members or doctors while they were detained, the group said.

Wanigasooriya, the military spokesman, said there had been no cases of rape or sexual harassments as described in the report.

"If there are proper complaints with the relevant authorities, the army is ready to investigate them," he said.

He said security forces rescued 300,000 civilians during the war and have resettled them, while another 12,000 ex-rebel combatants have been rehabilitated.

"None of these persons have come with a complaint of this nature. This is another lie the Human Rights Watch has released," he said.

Last week, U.N. High Commissioner for Human Rights Navi Pillay faulted Sri Lanka for failing to properly investigate reports of atrocities during the war, and said government opponents continue to be killed and abducted.

"The government's response to allegations of sexual violence by its security forces have been dismissive, deeming them as 'fake' or 'pro-LTTE propaganda,'" Adams said in a statement Tuesday. "It's not clear who in the government knew about these horrific crimes. But the government's failure to take action against these ongoing abuses is further evidence of the need for an international investigation."a